Construction and evaluation of an expression vector allowing the stable expression of foreign antigens in a Salmonella typhimurium vaccine strain at toxic levels.

Salmonella strains have great potential as live carriers of heterologous antigens to induce immunity against a variety of infectious diseases. However, the amount of heterologous antigen required to induce an adequate immune response may be toxic for the bacterium and result in cell death, overattenuation or loss of expression of the heterologous antigen. To solve this problem an expression vector was developed with a strong promoter located on a DNA fragment which is inverted at random. Antigen is only expressed in one particular orientation of the promoter. Thus a bacterial population harbouring the plasmid will consist o

Precise Measurement of Gravity Variations During a Total Solar Eclipse

The variations of gravity were measured with a high precision LaCoste-Romberg D gravimeter during a total solar eclipse to investigate the effect of solar eclipse on the gravitational field. The observed anomaly $(7.0 \pm 2.7) \times 10^{-8}$ m/s$^2$ during the eclipse implies that there may be a shielding property of gravitation

Localization of electromagnetic waves in a two dimensional random medium

Motivated by previous investigations on the radiative effects of the electric dipoles embedded in structured cavities, localization of electromagnetic waves in two dimensions is studied {\it ab initio} for a system consisting of many randomly distributed two dimensional dipoles. A set of self-consistent equations, incorporating all orders of multiple scattering of the electromagnetic waves, is derived from first principles and then solved numerically for the total electromagnetic field. The results show that spatially localized electromagnetic waves are possible in such a simple but realistic disordered system. When localization occurs, a coherent behavior appears and is revealed as a unique property differentiating localization from either the residual absorption or the attenuation effects

Potential Tumor Suppressor NESG1 as an Unfavorable Prognosis Factor in Nasopharyngeal Carcinoma

BACKGROUND:Recently we identified nasopharyngeal epithelium specific protein 1 (NESG1) as a potential tumor suppressor in nasopharyngeal carcinoma (NPC). The purpose of this study is to investigate the involvement of NESG1 in tumor progression and prognosis of human NPC. METHODOLOGY/PRINCIPAL FINDINGS:NESG1 protein expression in NPC was examined. Survival analysis was performed using Kaplan-Meier method. The effect of NESG1 on cell proliferation, migration, and invasion were also investigated. RESULTS:NESG1 expression was downregulated in atypical hyperplasia and NPC samples compared to normal and squamous nasopharynx tissues. Reduced protein expression was negatively associated with the status of NPC progression. Patients with lower NESG1 expression had a shorter overall survival and disease-free time than did patients with higher NESG1 expression. Multivariate analysis suggested NESG1 expression as an independent prognostic indicator for NPC patient survival. Proliferation, migration, and invasion ability were significantly increased in cell lines following lentiviral-mediated shRNA suppression of NESG1 expression. Microarray analysis indicated that NESG1 participated in multiple pathways, including MAPK signaling and cell cycle regulation. Finally, DNA methylation microarray examination revealed a lack of hypermethylation at the NESG1 promoter, suggesting other mechanisms are involved in suppressing NESG1 expression in NPC. CONCLUSION:Our studies are the first to demonstrate that decreased NESG1 expression is an unfavorable prognostic factor for NPC

Psychological Typhoon Eye in the 2008 Wenchuan Earthquake

BACKGROUND: On May 12, 2008, an earthquake measuring 8.0 on the Richter scale jolted Wenchuan, China, leading to 69,227 deaths and 374,643 injured, with 17,923 listed as missing as of Sept. 25, 2008, and shook the whole nation. We assessed the devastating effects on people's post-earthquake concern about safety and health. METHODOLOGY/PRINCIPAL FINDINGS: From June 4 to July 15, 2008, we surveyed a convenience sample of 2,262 adults on their post-earthquake concern about safety and health. Residents in non-devastated areas (Fujian and Hunan Provinces, and Beijing) and devastated areas (Sichuan and Gansu Provinces) responded to a questionnaire of 5 questions regarding safety measures, epidemic disease, medical workers, psychological workers, and medication. The ANOVAs showed a significant effect of residential devastation level on the estimated number of safety measures needed, the estimated probability of the outbreak of an epidemic, and the estimated number of medical and psychological workers needed (Ps<0.001). The post-earthquake concern decreased significantly as the level of residential devastation increased. Because of the similarity with the meteorological phenomenon of the eye of a typhoon, we dubbed these findings a "Psychological Typhoon Eye": the closer to the center of the devastated areas, the less the concern about safety and health a resident felt. CONCLUSIONS/SIGNIFICANCE: Contrary to common perception and ripple effect that the impact of an unfortunate event decays gradually as ripples spread outward from a center, a "Psychological Typhoon Eye" effect was observed where the post-earthquake concern was at its lowest level in the extremely devastated areas. The resultant findings may have implications for Chinese governmental strategies for putting "psychological comfort" into effect

Localization and Androgen Regulation of Metastasis-Associated Protein 1 in Mouse Epididymis

BACKGROUND: Metastasis-associated protein 1 (MTA1), the founding member of the MTA family of genes, can modulate transcription by influencing the status of chromatin remodeling. Despite its strong correlation with the metastatic potential of cancer cells, MTA1 can also regulate crucial cellular pathways by modifying the acetylation status. We have previously reported the presence of MTA1/MTA1 in human and mouse testes, providing the evidence for its involvement in the regulation of testicular function during murine spermatogenesis. The objective of present study was to further assess the localization of MTA1 in mouse epididymis on both transcriptional and translational level, and then to explore whether MTA1 expression is regulated by androgens and postnatal epididymal development. METHODOLOGY/PRINCIPAL FINDINGS: Mice were deprived of circulating androgen by bilaterally castration and were then supplemented with exogenous testosterone propionate for one week. MTA1 was immunolocalized in the epithelium of the entire epididymis with the maximal expression in the nuclei of principal cells and of clear cells in proximal region. Its expression decreased gradually after castration, whereas testosterone treatment could restore the expression, indicating that the expression of this gene is dependent on androgen. During postnatal development, the protein expression in the epididymis began to appear from day 7 to day 14, increased dramatically from postnatal day 28, and peaked at adulthood onwards, coinciding with both the well differentiated status of epididymis and the mature levels of circulating androgens. This region- and cell-specific pattern was also conservative in normal human epididymis. CONCLUSIONS: Our data suggest that the expression of MTA1 protein could be regulated by androgen pathway and its expression level is closely associated with the postnatal development of the epididymis, giving rise to the possibility that this gene plays a potential role in sperm maturation and fertility